1. Field Of The Invention
This invention relates to hazard warning devices such as are used to protect disabled vehicles on highways, and in other analogous applications.
2. Review Of The Prior Art
The device commonly used for the above purpose is a slow burning red pyrotechnic flare. Such flares have various disadvantages, of which some of the most evident are limited shelf life, susceptibility to damp, the use of highly combustible material, as well as the possibility of accidental burns to the user or the starting of fires if carelessly used. In addition, there is often no means available for supporting such flares in an upright position during use; their visibility may be considerably reduced if they lie flat on the ground. Such a flare can of course be used only once, and is difficult to extinguish once lit.
Another widely used form of hazard warning device is a reflective red triangle, which may be made collapsible and provided with an integral prop. Whilst easy to use, and having an indefinite life, it depends for its effectiveness upon the reflection of light transmitted by an approaching vehicle and is thus limited in its usefulness.
U.S. Pat. No. 2,237,536 to Wells discloses a portable light signal which motorists can set up in emergencies. The signal comprises a signal lamp, a cylindrical lamp shaft which holds the lamp and extendable support legs. Legs 23 are hinged at a medial portion of the lamp shaft. As shown in FIG. 3, when the legs are extended to support the signal, an end 31 of one of the legs engages a leaf spring contact 32 to complete the light circuit and to automatically actuate the light. See page 2, first column, lines 7-36.
U.S. Pat. No. 3,415,476 to McDermott discloses a collapsible stand for lighting devices. The support legs are hingably attached to the end of the lamp which comes into contact or near contact with the surface on which the lighting device is placed. When the device is not being used, the legs are pulled upward as shown in FIG. 7.
U.S. Pat. No. 4,447,802 to Bose and U.S. Pat. No. 2,972,739 to Opper disclose alternative structures used to support portable safety and warning lights.